Fluidized bed grain processor

ABSTRACT

A grain processor has an enclosure with top, side and end walls and a bottom wall having a number of perforated areas spaced by an imperforate zone. A weir extends between the side walls and is located above the imperforate zone. The weir is variably spaced from the top and bottom walls. A heater supplies hot air to the enclosure through the perforations. There is an air return from the enclosure to the heater. Grain is supplied to one end of the enclosure just above the bottom and is released from the other end of the enclosure.

[ 51 Jan. 21, 1975 FLUIDIZED BED GRAIN PROCESSOR [75] Inventor: John C. Whelan, Woodland, Calif [73] Assignee: California Pellet Mill Company, San

Francisco, Calif.

[22] Filed: Dec. 18, 1972 [21] Appl. No.: 316,114

[52] US. Cl. 34/57 R, 34/10 [51] Int. Cl F26b 17/10 [58] Field of Search 34/57 R, 57 C, 57 A, 10, 34/ DIG. 2, 15; 432/58 [56] References Cited UNITED STATES PATENTS 1,375,080 4/1921 Chappell 34/D1G. 2 2,490,176 12/1949 Tomlinson et al... 34/D1G. 2 2,797,908 7/1957 Zubrzcki 34/57 R 3,304,619 2/1967 Futer 34/10 3,409,025 11/1968 Wochnowski.... 34/57 R X 3,539,164 11/1970 Brachthauser 432/80 FOREIGN PATENTS OR APPLICATIONS 1,170,307 5/1964 Germany 34/20 1,185,704 3/1970 Great Britain 34/10 635,905 2/1962 Canada 1,293,023 4/1962 France 34/57 950,033 2/1964 Great Britain 34/57 C Primary ExaminerCharles J. Myhre Assistant Examiner-William C. Anderson Attorney, Agent, or FirmBruce & McCoy 5 7 ABSTRACT A grain processor has an enclosure with top, side and end walls and a bottom wall having a number of perforated areas spaced by an imperforate zone. A weir extends between the side walls and is located above the impcrforate zone. The weir is variably spaced from the top and bottom walls. A heater supplies hot air to the enclosure through the perforations. There is an air return from the enclosure to the heater. Grain is supplied to one end of the enclosure just above the bottom and is released from the other end of the enclosure.

8 Claims, 1 Drawing Figure PATENTEB JANZ I 875 FLUIDIZED BED GRAIN PROCESSOR It is of increasing importance, particularly in connection with large scale cattle feeding and the like, to provide feed grain in a predetermined condition to the cattle. Part of the conditioning of the grain involves heating it from a random or ambient temperature, as received, to a higher, predetermined or established temperature. Since such heating involves the utilization of heat which is relatively expensive, it is important to provide a grain processor which operates efficiently.

It is therefore an object of my invention to provide a grain processor that is particularly effective in subjecting grain to a heating current of hot air.

Another object of the invention is to provide a grain processor in which the grain being heated is uniformly treated in a relatively short space of time.

Another object of the invention is to provide a grain processor in which the received grain is agitated or tumbled or intermixed as it is being heated in order that each of the individual grains receives substantially the same heating treatment.

Another object of the invention is to provide a grain processor through which a large quantity of grain can be processed in a relatively short time.

A further object of the invention is in general to provide an improved grain processor.

Other objects together with the foregoing are attained in the embodiment of the invention described in the accopanying description and illustrated in the accompanying drawing, in which:

The FIGURE is a diagram, not to scale and partially in cross-section on a longitudinal vertical plane, of a grain processor constructed pursuant to the invention.

While the grain processor can be embodied in a large number of different forms, particularly depending upon its use and environment, the source of heat, the nature and amount of grain to be treated and the like, it has successfully been incorporated in one relatively small version as disclosed herein. In this instance there is provided a bin 6 or hopper or other holder to receive bulk grain in its natural condition and to hold such grain for subsequent treatment. The hopper 6 discharges by gravity through a vertical duct 7 having a lateral opening 8 at one end of an enclosure, generally designated 9, and extending for a substantial width, length and height. The opening 8 preferably extends across virtually the entire width of the enclosure. The enclosure 9 includes a top wall 11 conveniently of sheet metal or the like properly reinforced and likewise includes a pair of side walls designated 12 as well as a pair of end walls 13 and 14. The wall 13 includes the opening 8.

The bottom of the enclosure is bounded by a bottom wall extending under the duct 7 and being substantially flat and horizontal between the inlet 8 and an outlet 16 at the other end of the enclosure. The outlet 16 opens into a discharge duct 17 containing a grain release mechanism or valve 18.

The bottom wall is not solid. Rather, it is provided with a plurality of areas such as 21, 22 and 23 in which the sheet of the bottom wall is pierced by a plurality of perforations 24. These are conveniently made by piercing the sheet partially to afford an opening and a lip 26 outstanding from the sheet and inclined generally upwardly and in the direction of the outlet 16. The various areas 21, 22 and 23 of the perforations extend virtually entirely across the enclosure 9 and extend from the inlet 8 substantially to the outlet 16. They are also spaced apart each from the others by intervening zones 27 and 28, for example, in which the bottom sheet has no perforations but rather is imperforate or solid. The locations of the solid or imperforate zones are preferably evenely spaced between the inlet and the outlet. In a practical example they are disposed approximately two feet from each other.

Extending to the side walls 12 of the enclosure but spaced from the top wall 11 thereof, yet depending toward the bottom wall are weirs 30, 31 and 32. The weirs 31 and 32 especially are located directly above the zones 27 and 28. The weirs conveniently are metal plates designed to slide in guides 33 secured to the side 5 walls and movable with sufficient friction so that they will stay in any desired vertically adjusted position. Each weir can be spaced a desired or predetermined distance from the top wall 11 and, more particularly, a predetermined distance D from the bottom wall at the subjacent zone 27 or 28 to leave an opening 34.

The enclosure 9 is also provided with an air outlet 36 opening from the enclosure into a duct 37 leading to the tangential inlet of a separator 38 preferably of the cyclone type. The separator has a removable receiver 39 for deposited solids at its bottom. The separator also has a central outlet duct 41 leading to the inlet of an air blower 42 driven by an electric motor 43. The tangential outlet 44 of the blower extends through a heater 46. Air passing through the duct 44 has its temperature substantially raised in the heater and emerges from the heater at a predetermined temperature and humidity. Discharge air downstream of the heater 46 flows through a duct 47 extending to a plenum 48 at the bottom of the enclosure 9.

In the operation of this structure, the heater 46 is started and the motor 43 is energized. Air is circulated in a substantially closed circuit. Ultimately, hot air travels through the duct 47 and into the enclosure 9 through the apertures 24 in the bottom wall 14 thereof. The air is partially directed by the lips 26 in an upward direction toward the outlet and emerges from the apertures or perforations with considerable velocity. Grain in the hopper 6 travels by gravity through the opening 8. The individual grains become entrained in the airstreams emerging from the bottom wall perforations. The grain is thus lifted upwardly and also transported forwardly. It is tumbled and agitated so that it is exposed readily and thoroughly to the hot, processing air.

The grain is not permitted to move directly to the outlet 16. Because of its ebullient or partially airborn condition, the grain, unless restrained, tends to travel too quickly to the outlet and so is not uniformly processed. For that reason, the grain is initially partially confined or baffled by the weir 31. The air velocity and the dispositions of the structures are such that little or none of the agitated grain travels over the top of the weir 31. The conditions of the structure and its operation are such that grain near the bottom of the first weir is in effect made quite fluid by the entraining air flowing through the adjusted opening 34.

I have found during extensive tests that if perforations are included in the bottom area just below the weir 31; that is, if the imperforate zone 27 is not provided the desired operation of the structure is greatly interfered with. The grain does not then, in effect, flow virtually as a liquid from the upstream side of the weir 31 to the downstream side thereof. When the imperforate zone 27 is provided just below the weir there is a quiescent area with relatively high pressure on the upstream side and relatively low pressure on the downstream side. The grain is not then dissipated or blown back or away but advances very much as water would flow through the opening 34. The weir 31 is raised or lowered appropriately so that the rate or amount of flow through the opening 34 is substantially as desired and so that the average depth of grain is controlled.

Grain traveling from the opening 34 finds itself in a volume between the weirs 31 and 32 and is again subjected to air lifting because of the perforations 24 in the next perforate area 22. The lifting and tossing function is repeated. The further heated grain moves into another quiescent area under the weir 32 established by the imperforate zone 28. The grain, after having been tumbled in the intermediate volume and not being elevated sufficiently to travel over the top of the weir 32, finally flows under such weir through an opening 49 very much like the opening 34.

The opening 49 extends clear across the enclosure and takes a wide swath of grain from the intermediate compartment to the downstream compartment. The size of the opening 49 is regulated by the vertical position of the weir 32 to afford the desired average depth of grain and a proper outflow of grain to the downstream side of the weir. The grain is then in a third volume or compartment between the downstream side of the weir 32 and the end wall 14. The grain continues to tumble and be heated. The heated grain ultimately flows through the outlet 16 and into the duct 17 to travel past the valve 18 to discharge.

Air which has imparted heat to the grain and is largely cooled, flows through the air outlet 36 and the duct 37 into the separator 38. While this spent air is for the most part free of grain particles there is some carry over of chaff and light material. Solids entrained in the air fall out gravitally into the container 39 from which they can periodically be removed. The separated or cleaned air flows out of the separator through the duct 41 and is impelled ahead by passing through the fan 42. The discharge air from the fan then travels in the duct 44 and is reheated in the heater 46. This provides hot air for subsequent travel through the duct 47 and discharge from the plenum 48, as previously described.

In extensive practice I have determined that in a small grain dryer; for example, having the compartment or enclosure 9 substantially six feet in length, it is advisable to place the weirs 31 and 32 substantially 2 feet apart and 2 feet from the various end walls. If there is a greater spacing the tendency is for the grain to travel too far without being sufficiently tumbled. In larger units more weirs are used but with the maximum spacing of about 2 feet. I also have demonstrated that if the perforations 24 are continued through or into the zones 27 and 28 there is not an appropriate flow beneath the weirs 31 and 32. These then largely lose their regulating effect on the depth of the grain bed and on the virtually hydraulic flow of grain from the inlet opening 8 to the outlet 16.

l have found, for example, that it is important to maintain a somewhat empirically determined optimum depth of grain bed in order to provide efficient heat exchange between the hot air and the cool grain. With all other factors remaining constant, this exchange can vary as much as 50 percent simply by variation of the weir position; that is, the distance D. For example, in

one instance the goal was to heat wheat to 315 F. with air at 600 F. With an uncontrolled bed depth, or distance D; that is, without the weirs, the maximum output per hour of the unit was 5,400 pounds of processed grain. When the weirs were inserted and set at a particular depth; for example, a distance D of 1% inches between the bottom of the weir and the subjacent bottom plate 27, the output, other conditions being the same, rose to 6,400 pounds of processed grain per hour. Further, when the weirs were moved even farther down to leave only a 5 1 inch gap or distance D between the bottom of the weir and the bottom wall, the output increased to 8,100 pounds of processed grain per hour. This final distance D appeared to be, however, an optimum spacing under the stated operating conditions because further lowering of the weir apparently interfered unduly with lateral transfer of the grain and the total output decreased.

What is claimed is:

1. A grain processor comprising side, end and top walls partially defining an elongated enclosure; means for supplying untreated grain to one end of said enclosure; means for releasing treated grain from the other end of said enclosure; a stationary bottom wall for said enclosure having disposed therein a plurality of perforated areas spaced by at least one imperforate zone disposed between said ends; means for regulating the average depth of grain above said bottom wall including a vertically moveable weir located above each of said imperforate zones, said weir extending between said side walls and spaced from said top and bottom walls; and means for supplying fluidizing hot air to said enclosure through said perforated areas.

2. The grain processor of claim 1 wherein the means for supplying fluidizing hot air to said enclosure includes means for recycling the hot fluidizing air which has been used to treat the grain.

3. The grain processor of claim 1 wherein said stationary bottom wall includes at least two imperforate zones and attendant weirs for regulating the depth of the grain.

4. The grain processor of claim 1 wherein the openings of said perforated areas include lips or air deflectors.

5. The grain processor of claim 4 wherein said lips or air deflectors are inclined upwardly and in a direction to deflect air toward the grain release means.

6. The grain processor of claim 4 wherein the weirs are spaced approximately 2 feet apart.

7. The grain processor of claim 6 wherein the end weirs are spaced approximately 2 feet from the end walls.

8. A grain processor comprising side, end, and top walls partially defining an elongated enclosure,

means for supply untreated grain to one end of said enclosure means for releasing treated grain from the other end of said enclosure,

a stationary bottom wall for said enclosure having disposed therein a plurality of perforated areas spaced by at least two imperforate zones disposed between the ends of said enclosure, the openings of said perforated areas including lips or air deflectors which are inclined upwardly and in a direction to deflect air toward the grain release means,

means for regulating the average depth of grain above said stationary bottom wall including verti- 6 cally movable weirs located above each of said imand means for supplying fluidizing hot air to said en- Perforate Zones wens extendmg bctween 531d closure through said perforated areas for treating side walls and spaced from said top and stationary bottom walls, said weirs being disposed approximately 2 feet apart and approximately 2 feet from 5 treated 531d grameach of the end walls,

the grain and for recycling the hot air which has 

1. A grain processor comprising side, end and top walls partially defining an elongated enclosure; means for supplying untreated grain to one end of said enclosure; means for releasing treated grain from the other end of said enclosure; a stationary bottom wall for said enclosure having disposed therein a plurality of perforated areas spaced by at least one imperforate zone disposed between said ends; means for regulating the average depth of grain above said bottom wall including a vertically moveable weir located above each of said imperforate zones, said weir extending between said side walls and spaced from said top and bottom walls; and means for supplying fluidizing hot air to said enclosure through said perforated areas.
 2. The grain processor of claim 1 wherein the means for supplying fluidizing hot air to said enclosure includes means for recycling the hot fluidizing air which has been used to treat the grain.
 3. The grain processor of claim 1 wherein said stationary bottom wall includes at least two imperforate zones and attendant weirs for regulating the depth of the grain.
 4. The grain processor of claim 1 wherein the openings of said perforated areas include lips or air deflectors.
 5. The grain processor of claim 4 wherein said lips or air deflectors are inclined upwardly and in a direction to deflect air toward the grain release means.
 6. The grain processor of claim 4 wherein the weirs are spaced approximately 2 feet apart.
 7. The grain processor of claim 6 wherein the end weirs are spaced approximately 2 feet from the end walls.
 8. A grain processor comprising side, end, and top walls partially defining an elongated enclosure, means for supply untreated grain to one end of said enclosure means for releasing treated grain from the other end of said enclosure, a stationary bottom wall for said enclosure having disposed therein a plurality of perforated areas spaced by at least two imperforate zones disposed between the ends of said enclosure, the openings of said perforated areas including lips or air deflectors which are inclined upwardly and in a direction to deflect air toward the grain release means, means for regulating the average depth of grain above said stationary bottom wall including vertically movable weirs located above each of said imperforate zones, said weirs extending between said side walls and spaced from said top and stationary bottom walls, said weirs being disposed approximately 2 feet apart and approximately 2 feet from each of the end walls, and means for supplying fluidizing hot air to said enclosure through said perforated areas for treating the grain and for recycling the hot air which has treated said grain. 